Baghdad - The head of Iraq's biggest Sunni Muslim bloc in parliament was shot
dead at a mosque after delivering a sermon Friday, underlining fears that violence
might mount as U.S. forces prepare to withdraw from Iraqi cities before a deadline
in two weeks.

Harith al-Obaidi, 45, an outspoken critic of human rights abuses by security
forces inside Iraqi jails, was killed a day after he announced plans to summon
the ministers of interior, defense and justice to answer widespread allegations
of abuse and torture in Iraqi prisons.

"He unveiled cases of torture, and this did not please everybody,"
said Salim Abdallah, a lawmaker with a Sunni coalition known as the Iraqi Accordance
Front, which Obaidi headed. "This could hurt many influential people in
the military institution."

Prime Minister Nouri al-Maliki ordered an investigation into Obaidi's killing,
which he blamed on terrorists.

Maliki had warned at a gathering of hundreds of top military commanders from
across the country Thursday that "terrorist operations" could increase
ahead of the U.S. withdrawal from cities and a crucial vote for parliament next
January. He urged Iraqis to celebrate the U.S. withdrawal, which he called a
"victory," in "feast and festivals."

No one asserted responsibility for the attack. Some lawmakers suggested that
elements within the security forces might have had a hand in the assassination.
But other politicians said the killing, in a neighborhood that was once one
of Baghdad's most dangerous, was an attempt to reignite sectarian tension that
persists in Baghdad and other parts of Iraq. The attack also comes as politicians
have begun sometimes-tense deliberations over new coalitions ahead of the elections.

"This shows that the security situation is still fragile and dangerous,"
said Saleem al-Jubouri, a spokesman for the Iraqi Accordance Front. "The
government must provide more security."

Shortly after noon, a gunman in civilian clothes, who police said was 15 years
old, shot Obaidi twice in the back of the head, killing him instantly. Obaidi
had just finished delivering a religious sermon, as he does every Friday at
al-Shawaf mosque in the neighborhood of Yarmouk, in western Baghdad. In the
sermon, he called on authorities to investigate the widespread allegations of
torture in Iraqi prisons.

The gunman then threw a grenade at the crowd, killing three people and injuring
11. Witnesses said he tried to escape through a back door of the mosque but
was chased down and killed by guards.

The slain lawmaker's brother, Mohammad, said he believed that the guards had
helped the gunman enter the mosque. "It was an organized crime," he
said, sobbing.

Obaidi is the third lawmaker to be assassinated since parliament was elected
in 2005, when many Sunnis boycotted the vote.

Obaidi, a university professor with a doctorate in Islamic studies, had two
wives and seven children. His party is the General Conference of the People
of Iraq, one of three parties making up the Accordance Front, which has 44 seats
in the 275-member parliament. The two other parties in the bloc are the Iraqi
Islamic Party and the National Dialogue Council. He became head of the Sunni
bloc in parliament in May after his predecessor was chosen as speaker.

Obaidi's colleagues paid tribute to his beliefs, saying he would be missed
at a time when the prisoners still in Iraqi and U.S. custody remain a pressing
issue.

"It would be very difficult to replace a man of such high principles,"
said Abdul Kareem Samarrae, a lawmaker and spokesman for the Iraqi Islamic Party.